Please refer to FIG. 1, which is a prior art of an optical scanner of flat bed. A document window glass 12 is on a case 11 of optical scanner 1 for loading a document (not shown in figure) to be scanned. A driving device 13 drives an optical chassis 14 to linearly move along a guiding rod 15 in said case 11 for scanning said document to be scanned on said document window glass 12.
Please refer to FIG. 2, which is a sectional view of A-A section of said optical chassis 14. Optical chassis 14 comprises a hollow case 14, a light source 142 positioned a suitable position on a side of said hollow case 141, a light-guide means assembled by plural leaf springs 146 and plural reflection mirrors 143, a lens set 144 and a CCD 145. Said light source 142 emits a light to document on document window glass 12, the light continuously goes into said hollow case 141 of optical chassis 14, and plural reflection mirrors 143 of said light-guide means reflect the coming light to extend a length of the reflected light, another call is optical length; finally said lens set 144 focuses and forms the reflected light in said CCD 145 and CCD 145 transfers the focused and formed light to electronic signals.
There are two tremendous shortcomings on the light-guide means of the prior optical chassis 14 shown in FIGS. 1 and 2, one of them is a value for a total track for CCD 144 clearly focusing and forming an image is fixed (shown as a total value of Y1+Y2+Y3+Y4+Y5 in FIG. 2); another is any one of plural reflection mirrors is installed on a wrong position to easily cause an incorrect reflection angle, thus scanning quality is low and such mirror cannot be adjusted to correct the angle.
The current light-guide means in marketing generally has following inconvenient conditions: the first, inaccuracy of wrong angles causes low scanning quality; the second, remodeling different structures for different solutions, optical chassis dimensions, scanning dimensions (ex. A3, A4, etc.) or other total tracks, and above conditions are not suitable to the present economical and efficient society.
Based on the aforesaid issues, the present inventor of the patent has being studied and referred to practical experiences and theory for designing and effectively improving the prior arts.